Porous-cellulose particles and production method thereof, and cosmetic

Abstract

The porous-cellulose particles according to the present invention are constituted by gathered crystalline celluloses having a type I crystal form including a glucose molecule as a constitutional unit. That is, porous-cellulose particles having high sphericity have been achieved from a natural raw material. The porous-cellulose particles have an average particle diameter of 0.5 to less than 50 μm, a specific surface area of 50 to 1000 m2/g, and a sphericity of 0.85 or more. Cosmetic products containing such porous-cellulose particles have excellent texture properties.

The invention claimed is: 
     
       1. Porous-cellulose particles, each porous-cellulose particle comprising crystalline celluloses having a type I crystal form, wherein
 the crystalline celluloses includes a glucose molecule as a constitutional unit, and 
 the porous-cellulose particles have an average particle diameter d 1  of 0.5 μm to less than 50 μm, a specific surface area of 25 m 2 /g to 1000 m 2 /g, and a sphericity of 0.85 or more. 
 
     
     
       2. The porous-celluloses particles according to  claim 1 , which have a coefficient of particle variance (CV) of 50% or less. 
     
     
       3. The porous-cellulose particles according to  claim 1 , which have a pore volume (PV) of 0.2 ml/g to 5.0 ml/g. 
     
     
       4. The porous-cellulose particles according to  claim 3 , which have an average pore diameter (PD) of 2 nm to 200 nm. 
     
     
       5. The porous-cellulose particles according to  claim 1 ,
 wherein a ratio (d 2 /d 1 ) is in a range of 0.95 to 1.05, the d 2  is an average particle diameter of the porous-cellulose particles when an aqueous dispersion liquid of the porous-cellulose particles is dispersed by an ultrasonic disperser for 60 minutes. 
 
     
     
       6. The porous-cellulose particles according to  claim 1 ,
 wherein an average particle diameter d 3  of the crystalline celluloses is from 1 nm to 1 μm. 
 
     
     
       7. The porous-cellulose particles according to  claim 1 ,
 wherein the porous-cellulose particles are hollow particles having a cavity inside a shell. 
 
     
     
       8. A production method of the porous-cellulose particles according to  claim 1 , comprising:
 an emulsification step of mixing a dispersion liquid of crystalline celluloses having a type I crystal form, a surfactant, and a nonaqueous solvent to prepare an emulsified liquid containing emulsified droplets; 
 a dehydration step of removing water from the emulsified droplets; and 
 a step of separating the nonaqueous solvent dispersion body obtained in the dehydration step into solid and liquid to obtain porous-cellulose particles as solid matter. 
 
     
     
       9. The production method of porous-cellulose particles according to  claim 8 , wherein the dehydration step is performed after cooling the emulsified liquid obtained in the emulsification step to a range of 0° C. to −50° C. to obtain a frozen emulsified liquid in which water in the emulsified droplets is frozen and then returning the frozen emulsified liquid to normal temperature. 
     
     
       10. Cosmetic products containing the porous-cellulose particles according to  claim 1 .